Re: [Amforth-devel] Starting with amforth v4

[pito <pi...@vo...>]

Andy,
No, the wordlist is as printed out with "words". So lefthandside are
the newest defined.
Pito

----- PŮVODNÍ ZPRÁVA -----
Od: an...@ki...
Komu: "pito" <pi...@vo...>
Předmět: Re: [Amforth-devel] Starting with amforth v4
Datum: 4.7.2010 - 13:02:32

> The last definition you wrote is the one that gets
> run when you invoke
> the word.
> 
> So for :-
> 
> >> words
> > navigate distance position sinus sinus speed height
> > sinus ....
> > 
> ........................................................*
> 
> Assuming left hand side is the start or oldest end
> of the wordlist and
> right is the end or newest end of the wordlist. The
> asterisk is marking
> the one that would be used. The others are waste.
> 
> For the purposes of Space Technology this is actually
> a good feature.
> 
> Imagine that a stray bit of cosmic radiation zaps through
> your
> controllers memory and screws up the last sinus word
> in the list.
> 
> You dont want to try and recovery all the memory that
> the defintion
> occupied becasue there is no way for you to tell which
> bit has been zapped.
> 
> You just define sinus again. the new definition coming
> closer to the end
> of the list is used in preference to the screwed one
> and your satellite
> is returned to full service.
> 
> If you were developing code in situ as a development
> thing you would
> marker before you started. Develop and when happy invoke
> the marker and
> reload just the good code bits. Eliminating all the
> trial and error
> along the way.
> 
> FORTH has apparently been used in several space programs
> because of
> these types of features. ie your mission is remotely
> repairable and
> therefore less likely to fail.
> 
> Hope this helps.
> 
> Cheers
> 
> Andy Kirby
> 
> 
> 
> On 04/07/10 11:46, pito wrote:
> > Andy, after I rised the Q I did it directly with
> > my dev system. Frankly
> > > the way how it works is changing my understanding
> > for "interactivity".
> > > Basically you cannot delete wrong words so the space
> > occupied will grow.
> > > Imagine my apollo picosatellite flying in the space
> > and I am tweaking
> > > the sw in its guidance computer. So I have to have
> > at least a chance
> > > activate/deactivate specific words. As I've seen
> > the forth manual the
> > > last definition of a word is valid. So you may have
> > many words with
> > > same name, however the last one will be used (am
> > I right?) for "following"
> > > usage. Imagine wordlist:
> >> words
> > navigate distance position sinus sinus speed height
> > sinus ....
> > > 
> > The Q: which sinus word will be used in speed and
> > height calculations?
> > > 
> > Sorry for this elementar Q, however I think one has
> > to understand the
> > > concepts...
> > Pito
> > 
> > 
> > ----- PŮVODNÍ ZPRÁVA -----
> > Od: an...@ki...
> > Komu: amf...@li...
> > Předmět: Re: [Amforth-devel] Starting with amforth
> > v4
> > > Datum: 4.7.2010 - 12:02:46
> > 
> >> Interesting question.
> >>
> >> I am afraid my understanding is that when you marker
> >> >> you delete
> >> everything back to the marker. Other markers as
> >> well.
> >> >>
> >> Managing linked lists etc on microcontrolers with
> >> limited
> >> >> space can be
> >> problematic. You dont have the memory to reorganize
> >> >> the memory space to
> >> free up bits of space in the middle of lumps of
> >> good
> >> >> code. Who is to say
> >> that the next bit of code would fit that space ???
> >> >>
> >> The technique then is to purge from the end of the
> >> >> list wherever that
> >> may be back to the marker.
> >>
> >> So for
> >>
> >>> bla bla -foo3 hello hello -foo2 happy happy -foo1
> >>> >>>
> >> doing -foo2 would give you.....
> >>
> >>> bla bla -foo3 hello hello
> >>
> >> Doing -foo1 would be pointless.
> >>
> >> Doing -foo3 would give........
> >>
> >>> bla bla
> >>
> >> Happy to be told I have got the wrong end of the
> >> stick
> >> >> though.
> >>
> >> Cheers
> >>
> >> Andy Kirby
> >>
> >>
> >>
> >> On 03/07/10 19:53, pito wrote:
> >>> Matthias,
> >>> I see the marker usage with sieve example. If you
> >>> >>> mark the set of words
> >>>> with -foo2 where is the end of the marked area
> >>>> (as
> >>>> >>> you may have X words
> >>>> defined)? Is that the next new marker position?
> >>>> It
> >>>> >>> means (wordlist):
> >>>>
> >>> bla bla -foo3 hello hello -foo2 happy happy -foo1
> >>> >>>> <-----------> <---------------> <--------------->
> >>>> >>> the area of marker
> >>>>
> >>> -foo2
> >>>
> >>> bla bla -foo3 happy happy -foo1 
> >>> <-----------> <--------------->
> >>>
> >>> or
> >>>
> >>> bla bla -foo3 ...................happy happy -foo1
> >>> >>> ??
> >>>> <----------->                   <--------------->
> >>>> >>>>
> >>> My understanding is it works like a "file system"
> >>> >>> so a deleted -foo will
> >>>> create a free space for new words - am I right?
> >>>> >>> As I uploaded lot of stuff for my naive experiments
> >>> >>> and the word list
> >>>> is now very long so the way how the list is maintained
> >>>> >>> seems to be a
> >>>> challenge..
> >>> Pito
> >>>
> >>> ----- PŮVODNÍ ZPRÁVA -----
> >>> Od: "Matthias Trute" <mt...@we...>
> >>> Komu: "Everything around amforth" <amf...@li...>
> >>> > >>> >>>>>> Předmět: Re: [Amforth-devel] Starting with
> >>>>>> amforth
> >>>>>> >>> v4
> >>>> Datum: 3.7.2010 - 13:55:30
> >>>
> >>>> Hi Pito,
> >>>>
> >>>>> My previous Q to the interactivity - so my understanding
> >>>>> >>>>>>>> is you may delete
> >>>>>> words from flash w/o burning new image.
> >>>>
> >>>> Just do a 
> >>>>
> >>>> marker -foo 
> >>>> : bar ;
> >>>> : baz bar ;
> >>>> ... use bar and baz and...
> >>>>
> >>>> now get rid of bar
> >>>>
> >>>> -foo
> >>>>
> >>>> and both bar/baz and -foo are gone. The only real
> >>>> >>>> difference
> >>>>>> from a
> >>>> users point of view is some planning with the
> >>>> -foo
> >>>> >>>>>> thing. Most of my
> >>>> source files define such markes...
> >>>>
> >>>>> However let us mind the atmel
> >>>>> flash and eeprom endurance..
> >>>>
> >>>> I still use the very first atmegas for developing,
> >>>> >>>>>> they have seen
> >>>> versions pre-0.1 and still work. And replacing
> >>>> a
> >>>> >>>> DIP
> >>>>>> package is
> >>>> easy...
> >>>>
> >>>> Matthias
> >>>
> >>>
> >>>
> >>> ------------------------------------------------------------------------------
> >>> > >>> >>>>>> This SF.net email is sponsored by Sprint
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> >>> >>>> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> >>> >>>> > >>>> >>>> _______________________________________________
> >>>> >>> Amforth-devel mailing list
> >>> Amf...@li...
> >>> https://lists.sourceforge.net/lists/listinfo/amforth-devel
> >>> >>>>
> >>
> >> ------------------------------------------------------------------------------
> >> > >> >>> This SF.net email is sponsored by Sprint
> >> What will you do first with EVO, the first 4G phone?
> >> >> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> >> >> > >> >> _______________________________________________
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> >> > 
> > 
> >